There are more English words beginning with the letter s than with any other letter mainly because of clusters such as sc, sh, sp, and st. Followed by some distance are words that begin with p, c, d, m, and a.
According to Wolfram Language, a computational knowledge engine, in a list of 40,127 common words, s has 4,635 entries – as compared to x which only has 11. This simple Wolfram word cloud expresses the most frequent initial letters in the English language:
Bear in mind that the frequency of initial letters has no relationship to how often letters occur in English in general. E is the most common letter, followed by t and then a.
If you enjoy learning fun facts about the English language, you may be interested in reading about The Power of X, why Americans say /zee/ when the rest of the world says /zed/, or how the ampersand (&) was once part of the English alphabet!